vii INFECTION OF ANIMALS WITH PLAGUE 165 



clumps of B. pestis (see Fig. 79). In the liver the 

 capillary blood-vessels within the acini appear in some 

 places almost as if injected with B. pestis, while the liver 

 cells appear shrunk or full of fat globules. Sections 

 through the lungs show, besides B. pestis present in some 

 parts in the distended veins and capillaries of the minute 

 bronchi and alveolar walls, that the alveoli contain blood 

 and homogeneous exudation. Extravasation of blood en 

 masse occurs in many parts of the peribronchial and inter- 

 lobular connective tissue. Similar extravasations of blood 

 en masse, containing numerous B. pestis, are met with 

 in many places in the connective tissue between the 

 cortex and medulla of the kidney. And small branches 

 of veins in the cortex of the kidney, as also the capillaries 

 of the glomeruli, contain numbers of B. pestis, forming in 

 many capillaries continuous blocks. 



[As mentioned above, the naked-eye appearances and 

 cultural results of rat 2 were the same as those of rat 1, 

 and it is not necessary to describe again the appearances 

 of the sections made through the hsemorrhagic swollen 

 Peyer's patch, the mesenteric glands, the spleen, the liver, 

 and the kidney. They showed the same copious distribu- 

 tion of B. pestis in the blood-vessels, in the lymphatics, 

 and in the parenchyma.] 



From these observations it is seen that out of three 

 rats fed, two succumbed to plague ; that they showed not 

 only definite changes of the intestine, but in unmis- 

 takable manner the exact spot or portal of the infection. 

 Further, it is seen that not only was there abundance of 

 B. pestis in the interior cavity of the affected intestine, 

 but also that the lymphatics of the affected part of the 

 intestine (villi, mucosa, submucosa, and muscular coat), 



